Communication devices, such as cellular radiotelephones, in some systems, such as the Global System for Mobile communication (GSM), use a subscriber card, such as a subscriber identity module (SIM). A SIM, such as a "smart card," includes an integrated circuit storing a subscriber identification number (subscriber ID). A card reader in the communication device reads the subscriber ID from the integrated circuit and a processor in the communication device uses this subscriber ID to execute a protocol for making or receiving a call. The protocol communicates the subscriber ED to a base station of the system. The system uses the ID for billing the call to the subscriber's account.
By providing the subscriber ID on the subscriber card instead of in the communication device, the communication device is not restricted to a single billing account. Any subscriber can use the communication device by inserting their card into the card reader. Calls made while the card is loaded are billed to the account associated with the card.
Cards such as SIMs are available in different sizes. Chip cards are not much larger than the integrated circuit, and thus measure approximately 25 mm by 15 mm, and are approximately 0.75 mm thick. Large cards, such as credit card size SIMs, are approximately 85.5 mm long by 54 mm wide and approximately 0.75 mm thick. Communication devices typically accommodate either a chip size SIM or a large size SIM, but not both. However, because communication devices only accommodate a single size card, only those users having a card sized for a communication device's card reader can use the communication device.
Accordingly it is desirable to provide a communication device with a card reader that accommodates multiple sized cards.